644561748740183 has 2 divisors, whose sum is σ = 644561748740184. Its totient is φ = 644561748740182.

The previous prime is 644561748740171. The next prime is 644561748740219. The reversal of 644561748740183 is 381047847165446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644561748740183 - 2⁴ = 644561748740167 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644561748740113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322280874370091 + 322280874370092.

It is an arithmetic number, because the mean of its divisors is an integer number (322280874370092).

Almost surely, 2^{644561748740183} is an apocalyptic number.

644561748740183 is a deficient number, since it is larger than the sum of its proper divisors (1).

644561748740183 is an equidigital number, since it uses as much as digits as its factorization.

644561748740183 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 433520640, while the sum is 68.

The spelling of 644561748740183 in words is "six hundred forty-four trillion, five hundred sixty-one billion, seven hundred forty-eight million, seven hundred forty thousand, one hundred eighty-three".